This invention relates to electrical component inductor assemblies and, in particular, to assemblies of inductors and other electrical components, such as capacitors, and to methods of making the same.
Conventional inductor/capacitor assemblies, such as Butterworth filters include a bobbin having a plurality of coils wound thereon which are connected to a bank of separately mounted capacitors. Typically, two bobbins, provided with wound coils, are mounted on opposite sides of a bank of capacitors. The coils of each bobbin are connected to capacitor electrodes on the same side as the coil.
More specifically, referring to FIG. 1, there is illustrated an electrical schematic of a conventional Butterworth filter 10 which includes a bank of capacitors, C.sub.1 -C.sub.4, interconnected with a plurality of coils L.sub.1 -L.sub.6. Physically, referring to FIG. 2, the coils L.sub.1 -L.sub.6 are wound on first and second bobbins 11, 12 which are arranged on opposite sides of the bank of capacitors C.sub.1 -C.sub.4. More specifically, the coils L.sub.1, L.sub.2 and L.sub.3 are wound between respective flanges of the bobbin 11 and the coils L.sub.4, L.sub.5 and L.sub.6 are wound between respective flanges of the bobbin 12. The respective ends of the coils L.sub.1, L.sub.2 and L.sub.3 are connected to respective first electrodes 13 of the capacitors C.sub.1 -C.sub.4 on the side facing the coils L.sub.1, L.sub.2 and L.sub.3 and the respective ends of the coils L.sub.4, L.sub.5 and L.sub.6 are connected to respective second electrodes 14 of the capacitors facing the coils L.sub.4, L.sub.5 and L.sub.6.
One of the problems associated with the prior art filter is the necessity of using two bobbins.
Further, prior art bobbins employ flanges to provide predetermined spacing between the inductors so as to facilitate the winding process and to maintain the winding pitch between each inductor. Flanged bobbins, however, are more costly and space consuming than unflanged bobbins.
Additionally, in conventional assembly of the prior art filter, the coils are not connected to the capacitors until after the capacitors are mounted to a printed circuit board. As a result, testing of the filter cannot be done until after the capacitors and coils have been assembled on the printed wiring board and interconnected. Accordingly, testing of the filter is more complicated than if the filter could be tested prior to assembly on the board. Further, any defects in the filter require costly and time consuming repair procedures.
To address these problems an improved assembly and method of making has been proposed in related application Ser. No. 08/688,564, filed Jul. 28, 1996, and entitled "INDUCTOR ASSEMBLY AND METHOD OF MAKING SAME", the entire disclosure of which is incorporated herein by reference (hereinafter "the '564 application"). In accordance with the '564 application, an inductor assembly includes a plurality of electrical components, such as capacitors, attached to a flangeless bobbin at spaced locations. Respective coils are wound about the bobbin between adjacent ones of the plurality of electrical components, the spacing between adjacent electrical components determining the pitch of the coils wound therebetween.
The '564 application overcomes the problem of conventional assemblies by providing an inductor/capacitor assembly which utilizes a single bobbin and which can be separately tested.